Conventionally, for the purposes of protection and aesthetic appearance improvement, solid, semi-solid or liquid coating agent compositions have been applied to painted steel sheets of automobile bodies and other similar objects. As such coating agent compositions, known examples include a composition containing a moisture curable organopolysiloxane, an organic solvent, and a curing catalyst, and further containing a volatile organopolysiloxane oil and volatile dimethylpolysiloxane added thereto (Patent Literature 1), and a composition further containing a high-viscosity silicone rubber added thereto (Patent Literature 2). However, these compositions have difficulty exhibiting the water repellency for a long period because the non-reactive organopolysiloxane oil volatilizes and dissipates over time.
To solve the above problem, various compositions have been proposed each of which contains a moisture curable silicone oligomer, an organic solvent, a curing catalyst, and a silicone oil having a reactive functional group in the molecule. Patent Literature 3 disclose an example using a reactive silicone oil having reactive groups at both ends of the molecular chain, the reactive groups being selected from a carbinol group, a carboxyl group, an amino group, a hydroxyl group (a silanol group), and the like. Moreover, Patent Literatures 4 and 5 disclose examples each using a reactive silicone oil having an alkoxysilyl group at one end of the molecular chain. Further, Patent Literature 6 proposes an example using a reactive silicone oil having a carbinol group and/or an amino group at a side chain(s) of the molecule. Patent Literature 7 proposes an example containing a fluorine-containing alkoxysilane.